Differentiated thyroid cancer: a retrospective analysis of 832 cases from Greece

To analyse the initial manifestations, pathological findings, therapy, outcome and prognostic factors in patients with papillary and follicular carcinoma.

832 patients with well differentiated thyroid carcinoma managed in our department during a period of 30 years (1965-1995). Follow-up data were available for 609 patients for a mean of 5.5 years (range 1-38 years), the remainder having been lost to follow-up.

The patients were 677 (81%) with papillary and 155 with follicular carcinoma. They were predominantly female (75%), presenting mainly with a single nodule (53%), while at the time of diagnosis 72% had intrathyroidal carcinomas (class I), 17% had nodal metastases (class II), 7% soft tissue invasion (class III) and 4% distant metastases (class IV). Fifty-five percent of the patients had a complete thyroidectomy (36% had a near total or total thyroidectomy and 19% near total or total thyroidectomy plus block dissection), 2.6% received external radiotherapy and 94% had radioactive iodine as part of the treatment of the original disease. Kaplan-Meier survival analysis was used to calculate both cancer related mortality and disease free survival in the patients followed-up. Although mortality (21 cancer-related deaths) was slightly higher for follicular than papillary carcinoma (10% vs. 5% and 16% vs. 10% in 10- and 15-year survival, respectively) the difference was not statistically significant. Extent of disease at diagnosis, male sex, tumour size and age > 60 years affected probability of cancer death. Cox's proportional hazard regression analysis for disease free survival showed that adverse independent prognostic factors were, for papillary carcinoma, male sex, class II or higher, tumour size > 1 cm and age > 60 years, while for follicular, class III or higher, size > 4 cm and age > 40 years.

We conclude that there is a higher prevalence of follicular carcinoma in our country probably due to a moderate degree of iodine deficiency still existing in Greece. Age and extent of disease at diagnosis were important prognostic factors affecting morbidity and mortality, whereas sex, tumour features and histological type were of minor importance. All these prognostic factors and their relative importance should be taken in consideration in the management of this disease.